Re: [PATCH net v2 2/2] vsock/test: add test for small packets under pressure

[Stefano Garzarella <sgarzare@redhat.com>]

On Wed, Jul 08, 2026 at 06:59:41AM -0400, Michael S. Tsirkin wrote:
>On Wed, Jul 08, 2026 at 12:29:04PM +0200, Stefano Garzarella wrote:
>> From: Stefano Garzarella <sgarzare@redhat.com>
>>
>> Add a test that sends 2 MB of data using randomly sized small packets
>> (129-512 bytes) over a SOCK_STREAM connection. Packets above
>> GOOD_COPY_LEN (128) bypass the in-place coalescing in recv_enqueue(),
>> forcing each one into its own skb.
>>
>> Without receive queue collapsing, the per-skb overhead eventually
>> exceeds buf_alloc and the connection is reset. The test verifies
>> that all data arrives and that content integrity is preserved.
>>
>> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
>
>maybe cut down SO_VM_SOCKETS_BUFFER_SIZE? will make it easier to
>trigger?

Currently, with the default value, the trigger is practically immediate 
for packets between 129 and 512 bytes, but yes, a smaller buffer size 
certainly makes this effect even more pronounced.

>
>anyway
>
>Acked-by: Michael S. Tsirkin <mst@redhat.com>

Thanks!

If I need to post a v3, I'll add it; otherwise, I guess we can leave it 
as is or send a follow-up for net-next.

Thanks,
Stefano